For a subexpression
env,
get_domain(env) is expression-equivalent to
MANDATE-NOTHROW(D()),
where
D is the type of the first
of the following expressions that is well-formed:
auto(AS-CONST(env).query(get_domain)). get_completion_domain<set_value_t>(get_scheduler(env), HIDE-SCHED(env)). default_domain(), except that
env is evaluated
.